28813931 has 2 divisors, whose sum is σ = 28813932. Its totient is φ = 28813930.

The previous prime is 28813919. The next prime is 28813957. The reversal of 28813931 is 13931882.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28813931 - 2¹⁰ = 28812907 is a prime.

It is a super-2 number, since 2×28813931² = 1660485239345522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_1788830 and since 28813931 and 1788830 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 28813891 and 28813900.

It is not a weakly prime, because it can be changed into another prime (28813901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14406965 + 14406966.

It is an arithmetic number, because the mean of its divisors is an integer number (14406966).

Almost surely, 2^28813931 is an apocalyptic number.

28813931 is a deficient number, since it is larger than the sum of its proper divisors (1).

28813931 is an equidigital number, since it uses as much as digits as its factorization.

28813931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 28813931 is about 5367.8609333700. The cubic root of 28813931 is about 306.5731884013.

The spelling of 28813931 in words is "twenty-eight million, eight hundred thirteen thousand, nine hundred thirty-one".